/**
 * SPINdle (version 2.2.2)
 * Copyright (C) 2009-2012 NICTA Ltd.
 *
 * This file is part of SPINdle project.
 * 
 * SPINdle is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * SPINdle is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with SPINdle.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @author H.-P. Lam (oleklam@gmail.com), National ICT Australia - Queensland Research Laboratory 
 */
package spindle.engine.sdl;

import java.util.List;

import spindle.core.dom.Rule;
import spindle.core.dom.Superiority;
import spindle.engine.TheoryNormalizerException;
import spindle.sys.AppFeatureConst;
import spindle.sys.message.ErrorMessage;

/**
 * SDL Theory Normalizer (version 2).
 * <p>
 * Provides methods that can be used to transform a defeasible theory into an equivalent theory without superiority
 * relation or defeater using the algorithms described in:
 * <ul>
 * <li>G. Antoniou, D. Billington, G. Governatori and M.J. Maher (2001) Representation Results for Defeasible Logic,
 * <i>ACM Transactions on Computational Logic</i>, Vol. 2 (2), pp. 255-287</li>
 * </ul>
 * </p>
 * 
 * @author H.-P. Lam (oleklam@gmail.com), National ICT Australia - Queensland Research Laboratory
 * @since version 2.2.1
 * @version Last modified 2012.08.20
 */
public class SdlTheoryNormalizer2 extends SdlTheoryNormalizer {

	public SdlTheoryNormalizer2() {
		super();
	}

	/**
	 * transform the theory to regular form and defeasible rules with multiple heads to single headed rules.
	 */
	@Override
	protected void transformTheoryToRegularFormImpl() throws TheoryNormalizerException {
		if (AppFeatureConst.isVerifyConflictRules) {
			List<Superiority> superiorities = theory.getAllSuperiority();
			for (Superiority superiority : superiorities) {
				String superiorRuleId = superiority.getSuperior();
				String inferiorRuleId = superiority.getInferior();

				Rule superiorRule = factsAndRules.get(superiorRuleId);
				Rule inferiorRule = factsAndRules.get(inferiorRuleId);

				if (null == superiorRule) throw new TheoryNormalizerException(getClass(),
						ErrorMessage.THEORY_SUPERIOR_RULE_NOT_FOUND_IN_THEORY, new Object[] { superiorRuleId });
				if (null == inferiorRule) throw new TheoryNormalizerException(getClass(),
						ErrorMessage.THEORY_INFERIOR_RULE_NOT_FOUND_IN_THEORY, new Object[] { inferiorRuleId });

				if (!superiorRule.isConflictRule(inferiorRule)) throw new TheoryNormalizerException(getClass(),
						ErrorMessage.SUPERIORITY_UNCONFLICTING_RULES, new Object[] { superiorRuleId, inferiorRuleId });
			}
		}
		
		super.transformTheoryToRegularFormImpl();
	}

}